In the past, snap fasteners have been, for the most part, “friction fasteners” and as such, they have taken considerable force to fasten together. Generally, they are not secure fasteners, as the force to separate them is in general no more than the force required to fasten them. Faults of snap fasteners previously known in the art have lead to losses (e.g. articles falling from holsters or cases which use these fasteners to secure closures). These faults include critical dimensional tolerances, which if not maintained, produce difficulty in closure and failure to stay closed. Wear of the fasteners can change these critical dimensional tolerances, causing looseness and failure to stay closed.
Some previously known fasteners, such as U.S. Pat. No. 3,538,557, are positive holding fasteners having female part with a resilient clamp including fingers that are engageable with a groove in the male part for separably coupling the male and female parts together. These fasteners, although positive in connection, are sometimes difficult to separate, because the resilient clamp is only about one half the diameter of the snap fastener and has a poor operating leverage ratio, it can be difficult to operate when made in small sizes.
U.S. Pat. No. 5,189,768 was an attempt to improve the release of this kind of snap fastener by adding a separate booster spring to aid separation. However, it retains the fault of a poor operating leverage ratio and the small resilient actuator plate makes using the snap fasteners difficult when made in small sizes. Further, it is difficult to construct because the actuator plate is a part of the resilient clamp.
Various quick-release devises can be found in the known art for disengaging a load when the load is either attached or suspended from a hook. While many of these devices are suitable for some applications, they generally become difficult or become incapable of release actuation when built in very small sizes because the load exerted on the jaws of the device is often transmitted to the latching mechanism, jamming the mechanism. In addition to operational deficiencies the known art devices often are complicated and structurally heavy, in comparison to the loads they are able to carry. For these reasons, quick-release devices of the general type have limited application in very small sizes and have achieved limited acceptability in the field. Typical remote coupling or locking devices found in the known art are represented by the following: U.S. Pat. Nos. 1,576,352; 1,824,843; 2,894,763; 3,403,650; 4,379,579; and 4,613,180. These devices are primarily single point connection devices and do not offer stability for the connected device during release. Accordingly, there exists a substantial need for an electro-mechanical quick-release device which is efficient, effective and inexpensive to manufacture and can be made in micro sizes.